In my world an advanced alien civilization are worshiped as gods by the human population. As the gods have better things to do than actually spend time interacting with the local fauna they created a hybrid through genetic engineering, combining traits of both their own species and humanity to create something closer to humans in thoughts and feelings to interact through. Humanity perceive these hybrids as demigods much akin to classic Greek heroes like Herakles and the like.

The alien technology is treated like magic, and can only be utilized by the demigods*. The reason for this is that the alien tech is more or less programmed to only respond to beings with the gods' genetic code.

The demigods must place their God-Hand, their right hand that is designed to be similar to their divine progenitors, on the device to activate it.

My question is are there any good reasons why they may need to utilize their god-hand specifically? My understanding of genetics would lead me to think no part of their body is technically more or less "alien" than another, even if the body exhibits more traits from the alien side than the human.

Further Information: These hybrids are the product of very advanced genetic engineering and were specifically designed the way they were. I do not know if this makes the god-hand more or less likely to make sense.

Note*: I had intended for humans to be able to utilize the god-tech by using the blood of demigods to fool the devices into letting them access the controls.

More Information: The humans are pre-industrial on a planet with very little easily accessible precious metals, forcing them to exist in a pseudo-stone age level of technology.

  • $\begingroup$ Could you define "divine blood"? Does it mean "you have to have the blood of gods inside you" or "it requires a literal blood donation"? Or something else? Or is it not really defined? $\endgroup$
    – VLAZ
    Commented May 22, 2019 at 6:39
  • $\begingroup$ It means the literal blood containing alien genetic code. In my mind humans could use the blood by basically pouring it on the machine and placing their hand over it. The machine scans the blood, detects the alien DNA, and allows access. In theory god-saliva and other bodily fluids may work as well, but good luck harvesting it in sufficient quantities. $\endgroup$ Commented May 22, 2019 at 7:01
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    $\begingroup$ Easy: left handed people are evil, and the equiment was deliberately made to exclude these unnatural mutations. $\endgroup$ Commented May 22, 2019 at 8:34

5 Answers 5


Hand design

The weapons require inhuman hand to hold it. It's not merely "fingerprints" but the weapons are designed for an entirely alien hand. Maybe it's larger than the human's maybe it's smaller. Perhaps it has three fingers only, perhaps it has seven. This is up to you to design.

It's both part of the design and part of the protection it has from humans - unlike a normal pistol, a human can't just take it and immediately use it.

A "demigod" is genetically engineered to different but their right hand is actually disguising their alien hand. Details up to you again, but I imagine it being able to extend and split somewhat similar to cybernetic hands Ghost in the Shell as it can be suitably discreet and also allow for some bizarre mechanisms on the devices:

Ghost in the Shell GIF of cybernetic hands expanding

This is intentional both for protection of the devices and the hybrids, as well as keeping the mystery around the "godly powers" - a seemingly non-alien can use the tech or "magic" while humans cannot.

Something to keep in mind - given enough time and technological level, humans should be able to adapt this technology to be used by them. How exactly is up to you but it will likely make it awkward to use - perhaps humans need two hands or maybe two of them are needed to operate it. This makes the tech still alien but usable to humans.

Blood requirement

This has been put in place as a safeguard against the hybrids. Just so they don't get drunk with power or even turn on their creators. The weapons literally require blood to power them. The aliens might have gene-modded the hybrids to have blood actually be some sort of fuel, or it might not be.

At any rate, once the hybrid takes hold of a device, some amount of their blood is extracted with activation. This ensures that a hybrid cannot use a device too often or else they would die.

The blood need not come from the God-Hand but the God-Hand might be designed to easily facilitate this with some sort of opening to a vein that fits into the mechanism and makes the transfer painless.

Humans seeking to use the alien devices would require blood from the hybrids. So, they might need to hunt down "demigods" to gain more blood. An even darker twist would be capturing the hybrids and harvesting blood from them.

A somewhat obvious plot hook here is that if aliens designed the blood requirement to limit the power each individual hybrid can wield, an ambitious demigod could just use other demigods' blood instead of sacrificing his own, which means he can use alien tech with a lot less restrictions. Be that in order to rule over the entire world or even take the fight to his creators or something else would depend on the story. Whatever the case, it can serve as a vehicle to have a "religious war" sparked where one (or more) demigods start a struggle for dominance and aim to capture other demigods.

  • 2
    $\begingroup$ This is a brilliant answer that both solves the problem I was having and adds a new twist I hadn't considered. Very good. I never thought of the weapons effectively being vampiric and needing blood to function. Nor that the hand may be engineered to allow easier access to their blood. $\endgroup$ Commented May 22, 2019 at 7:45

Blood Veins

The question here is that what does the God Hand has to have different from a human hand to be recognized by the machine, but we are limiting our thoughts only on the outside factors like FingerPrints, I suggest you picture the inside of a hand.

Your God hand may not need to look different than a normal human hand, in fact, it may look exactly like a human hand, but all it needs is to have a different structure inside it.

In a human hand, there are bones, blood veins, arteries, capillaries (I am not a doctor though). But your god hand may have an entirely unique set of things like (I don't know) bones with an alien specific grain structure, different size of blood veins, no capillaries or literally whatever you wish for.

Your alien machine works something like this: when a god hand is placed on it, the machine scans the inside of the hand, (but you can't tell just by looking at it) and recognizes the alien hand and along with this it puts a needle inside the palm to take blood sample for DNA matching.

Now it will get tricky when humans want to use it, in this case, they might have to have the full god hand, or just the palm to use it, if humans are advance or can steal god tech, they may acquire a 3D printer to print a god hand of their own or they can simply take one off from the demigod.


Hereditary crystal.

  1. Demigodhood is passed thru the mother. Male demigods can conceive offspring who might be different than regular humans, but their children do not have Godhand.

  2. Demigods have a crystal, or jewel, or pearl within the tissues of the hand. That is how the Godhand works. It is like an RFID chip. The lineage of a given demigod can be traced through the nature of the crystal. A demigod may or may not know how it works.

  3. When a demigod is pregnant, a piece of her own crystal breaks loose and makes its way into the fetus. Maybe it goes directly to the hand or maybe it migrates from inside the body out to the hand during childhood.

  4. The mother does not lose enough crystal to make a difference. She gradually regrows what she has lost.

  5. The child's crystal will grow with the child; at some point it is big enough / in the right location to be used as the Godhand.

  6. The crystal quickly loses its power if removed from a living body or if life is removed from the body it is in. But possibly it might be transferred...


If your aliens are intentionally posing as gods, they probably will use the hand as symbol of their power. Thus the device designed to have a hand slot, which in reality unlocked by genetic code and activated by pressure.


The tech has biometric authentication akin to the fingerprint authentication on some phones, and requires alien fingerprints in order to activate. Human fingerprints fail this test, so they have to use their alien-shaped hand to activate them.

This would also allow humans to hypothetically bypass these restrictions by using something like sticky tape to copy the alien fingerprints; the Mythbusters have proven that it's possible to do so for human fingerprint biometric security.

  • $\begingroup$ This was my first thought as well, but it runs into the issue of humans using divine blood to fool the system. I'd need another way for humans to fake the alien finger prints. Or just straight up cut off a demigod's hand I suppose. $\endgroup$ Commented May 22, 2019 at 5:50
  • 1
    $\begingroup$ You can fool fingerprint scanners using sticky tape. The Mythbusters made an episode about it. $\endgroup$
    – nick012000
    Commented May 22, 2019 at 5:51
  • $\begingroup$ OP probably needs blood activation to make it look like blood magic. $\endgroup$ Commented May 22, 2019 at 6:11

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